Various methods for installing cables into tubes are known.
For example, European Patent No. EP 0,292,037 (and its counterpart U.S. Pat. No. 4,934,662), recognize that compressed air flow passed through a duct exerts a drag force on a cable being introduced into the duct, thereby pulling the cable through the duct towards the duct outlet. U.S. Pat. No. 4,934,662 is hereby incorporated by reference in its entirety.
U.S. Pat. No. 5,946,788 discloses a method for inserting a cable into tubular sheathing that is wound on a reel. The reel is subjected to a periodic movement having a vertical component and a longitudinal component upon introduction of the cable into the tubular sheathing. The vertical component comprises a vertical oscillation, which is alternately directed upwards and downwards (i.e., opposite to and in the direction of gravity). The longitudinal component may be regarded as an oscillating rotation. It is assumed that the cable is not in frictional contact with the tubular sheathing during free-fall movement of the reel and is thus capable of moving forward within the tubular sheathing without friction. U.S. Pat. No. 5,946,788, however, discloses an exemplary oscillation angle of only about 6° for the longitudinal component. U.S. Pat. No. 5,946,788 is hereby incorporated by reference in its entirety.
International Application No. WO 98/26320 (and its counterpart U.S. Pat. No. 5,950,298) disclose a method for inserting a cable into a tube wound on a reel. The tube reel is subject to a vertical movement during cable insertion. U.S. Pat. No. 5,950,298 is hereby incorporated by reference in its entirety.
U.S. Pat. No. 6,179,269 discloses a method and a device for installing a cable into coiled tubing. The introduction of the cable is carried out by employing a so-called compression station and a tension station. The compression station exerts a compressive force on the cable to urge the cable into the tubing. The tension station is disposed at the end of the tubing for pulling the cable out of the tubing. Such an installation is only suitable, however, for installing cables that can be subjected to a high pulling force. U.S. Pat. No. 6,179,269 is hereby incorporated by reference in its entirety.
These methods notwithstanding, there continues to be a need for an improved apparatus and method for inserting cabling (e.g., microducts) into cable guide tubing, especially prefabricated duct that is wound on a reel.